黏弹性溶剂中胶体流变行为的多粒子碰撞动力学模拟

The dispersions of colloids in viscoelastic solvents such as polymer have many applications like new functional materials. It is a challenge that how to better study and more efficient control the assembly behavior of colloids in viscoelastic solvents. It has been proved as an efficient method that applying external shear field to direct the assembly of colloids in viscoelastic solvents. However, the corresponding mechanism and kinetics process are still unclear. In this project, we attempt to apply multiparticle collision dynamics simulation (MPC)to study the flow behavior of colloids in viscoelastic solvents. MPC simulation is very suitable to study polymer, colloid and other soft matter. It has been proved that an effective viscoelastic solvent can be introduced into MPC simulation by applying dumbbell as solvent and the flow behavior of colloids can be examined further. In this project, the effects of the viscoelasticity of solvents, shear rate and others on the flow behavior of colloids will be examined and the relationship between rheological properties and material structures will be constructed. It is expected that the project can reveal the mechanism and kenitic process of flow-induced assembly of colloids in viscoelastic solvents. The study might be helpful for designing new materials, developing new technology in microfluidic fuild and understanding the related phenomena observed in life science.

胶体/黏弹性溶剂（如高分子）体系在新型功能材料研发等领域有着广泛的应用。如何更好地研究及有效地调控胶体/黏弹性溶剂的组装行为是目前研究的一个挑战。外加流场是调控胶体/黏弹性溶剂组装的有效方法，然而其具体调控机理及动力学过程仍不清晰。本项目拟用利用多粒子碰撞动力学模拟（MPC）对胶体在黏弹性溶剂中的流变行为进行研究。MPC模拟适于研究高分子、胶体等软物质，研究表明，利用dumbbell可以在MPC 中高效地引入黏弹性溶剂，进而可以实现对胶体流变行为的考察。本项目拟考察溶剂黏弹性、剪切速率等因素对胶体流变行为的影响，并构建材料流变性能与结构的关系。预期研究结果能够阐明胶体流致组装的机理及其动力学过程。本项研究有望为新材料的设计，微流控等新技术开发等提供理论指导，还有助于对相关生命活动的认识。

溶剂的黏弹性对分散于其中的胶体、细胞、高分子等的行为有着重要的影响，对新材料的制备，微流控等技术的开发有着重要的意义。本项目对胶体粒子在黏弹性溶剂中的流变行为进行研究。在本项目的资助下，我们在多粒子碰撞动力学模拟（MPC）中开发了一种新的黏弹性溶剂，利用dumbbell不仅可以考察溶剂的黏弹性，而且模拟效率高。在此基础上，我们考察了单个胶体的流变行为以及多个胶体的协同流变行为，考察了胶体、流场、溶剂等的影响。我们的研究为理解溶剂黏弹性对胶体的影响提供了理论参考。本项目培养了5名研究生。